The experiement failed, not the teacher. I had a problem also with
one brand of shaving cream it just did not work, maybe it was not
alcohol based. I used as coloring the liquid water color (you know the
ones that come in a jar) not mixing it up from the dry, so I am not sure
about the watered down tempera or watered down watercolor. I did
however have problems with one of the colors of the liquid watercolor.
Not all of them work equally. Bunki seems to have done more
experimenting than I did, so hopefully she will respond also, with her
words of wisdom. Your not a failure your on your way to being an expert
on this, you have personal experience of two things that don't work.